http://margo.student.utwente.nl/el/
ports/i2c

i2c       .zip    Algorithm for accessing an I2C bus.
i2c_faq   .zip    I2C FAQ by Vincent Himpe.
pci2c     .zip    Philips I2C monitoring program !! It uses the PC printerport.
pci2cbd   .zip    Schematic (only a few ports) for using the Philips I2C monitoring program.

On the The Hardware Book pages there's really a lot more info about all kinds
of connectors, cables and adapters.

Also look in the /micros section for I2C algorithms and hardware.

http://www.ping.be/~ping0751/i2c.htm is also a nice i2c place.